U.S. patent number 7,954,756 [Application Number 12/648,767] was granted by the patent office on 2011-06-07 for flap actuator.
This patent grant is currently assigned to Eaton Corporation. Invention is credited to Don R. Cavalier, Aaron M. Klap.
United States Patent |
7,954,756 |
Cavalier , et al. |
June 7, 2011 |
Flap actuator
Abstract
A flap actuator is provided for controlling movement of a flap
on a wing of an aircraft. The flap actuator includes a housing
having a leading end and a trailing end. A ball nut is rotatably
supported in the housing. A motor has a rotatable drive shaft that
is rotatable in first and second opposite directions. A gear
assembly translates rotation of the drive shaft to the ball nut. A
ball screw extends along a longitudinal axis and has a terminal end
operatively connectable to the flap. The ball screw is movable
between a first retracted in response to rotation of the ball nut
in a first direction and a second extended position in response to
rotation of the ball nut in a second direction. A one-way roller
clutch is operatively connectable to the ball nut. The roller
clutch engages the housing and prevents rotation of the ball nut in
a first direction in response to a compressive force on the ball
screw by the flap. First and second concentric gimbals are
positioned about the longitudinal axis adjacent the housing. The
gimbals interconnect the housing to the wing.
Inventors: |
Cavalier; Don R. (Walker,
MI), Klap; Aaron M. (Grand Rapids, MI) |
Assignee: |
Eaton Corporation (Cleveland,
OH)
|
Family
ID: |
38952078 |
Appl.
No.: |
12/648,767 |
Filed: |
December 29, 2009 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20110108664 A1 |
May 12, 2011 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
11458001 |
Jul 17, 2006 |
7690597 |
|
|
|
Current U.S.
Class: |
244/99.2;
244/215; 244/213 |
Current CPC
Class: |
F16H
25/2454 (20130101); B64C 13/341 (20180101); F16H
2025/2084 (20130101); F16H 25/2021 (20130101); F16H
2025/2071 (20130101) |
Current International
Class: |
B64C
3/38 (20060101); B64C 5/10 (20060101); B64C
9/00 (20060101); B64C 13/00 (20060101) |
Field of
Search: |
;244/99.2,213,215,216
;74/89.38,89.39 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1426290 |
|
Jun 2004 |
|
EP |
|
2858035 |
|
Jan 2005 |
|
FR |
|
675606 |
|
Jul 1952 |
|
GB |
|
Primary Examiner: Dinh; Tien
Assistant Examiner: Bonzell; Philip J
Attorney, Agent or Firm: Boyle Fredrickson, S.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional of application Ser. No. 11/458,001
filed Jul. 17, 2006 now U.S. Pat. No. 7,690,597.
Claims
We claim:
1. A flap actuator for controlling movement of a flap on a wing of
an aircraft, comprising: a housing having a leading end and a
trailing end; a ball nut rotatably supported in the housing; a ball
screw extending along a longitudinal axis and having a terminal end
operatively connectable to the flap, the ball screw movable between
a first retracted position and a second extended position in
response to rotation of the ball nut; a one-way roller clutch
operatively connectable to the ball nut, the roller clutch engaging
the housing and preventing rotation of the ball nut in a first
direction in response to a compressive force on the ball screw by
the flap; and a gimbal assembly connected to the housing and being
connectable to the wing, the gimbal assembly including: a first
gimbal for interconnecting the housing to the wing; a second gimbal
for interconnecting the housing to the wing; first and second
housing mounting pins interconnecting the first and second gimbals
to the housing; and first and second wing mounting pins
interconnecting the first and second gimbals to the wing.
2. The flap actuator of claim 1 wherein: rotation of the ball nut
in a first direction causes the ball screw to move toward the
extended position; and rotation of the ball nut in a second
direction causes the ball screw to move toward the retracted
position.
3. The flap actuator of claim 1 further comprising an inner bar
extending through the ball screw.
4. The flap actuator of claim 1 further comprising; a motor having
a rotatable drive shaft, the drive shaft rotatable in first and
second opposite directions; and a gear assembly for translating
rotation of the drive shaft to the ball nut.
5. The flap actuator of claim 4 wherein the gear assembly includes
a clutch, the clutch disengaging the drive shaft from the ball nut
in response to a predetermined force thereon.
Description
FIELD OF THE INVENTION
This invention relates generally to aircrafts, and in particular,
to a flap actuator for controlling operation of a flap on the wing
of an aircraft.
BACKGROUND AND SUMMARY OF THE INVENTION
The maneuverability of an aircraft depends heavily on the movement
of hinged sections or flaps located at the trailing edges of the
wings. By selectively extending and retracting the flaps, the
aerodynamic flow conditions of the wings may be influenced so as to
increase or decrease the lift generated by the wings. For example,
during the take-off and landing phases of a flight, the position of
the flaps of the aircraft are adjusted to optimize the lift and
drag characteristics of the wing. It can be appreciated the
reliable operation of the flaps is of critical importance to an
aircraft.
In large aircraft, a series of flaps are provided on the trailing
edge of each wing. The flaps are raised and lowered in a
conventional manner by a hydraulically actuated linkage of bell
cranks, pushrods, and idlers. A flap control lever is provided in
the cockpit of the aircraft to control the system mechanically. The
flap control lever is connected by conventional and teleflex cables
to a hydraulic actuating mechanism. As is known, these hydraulic
actuating mechanisms utilize large centralized pumps to maintain
pressure hydraulic pressure within the system. Hydraulic lines
distribute the hydraulic fluid under pressure to corresponding flap
actuators. In order to insure the reliability of the system,
multiple hydraulic lines are run to each flap actuator.
While functional for their intended purposes, these prior hydraulic
systems have certain inherent problems. For example, it is highly
desirable for all systems on an aircraft to be easily serviceable
so that departure of the aircraft will not be delayed while
mechanics attempt to diagnose and repair the aircraft. However,
given the complexity of the pumps and the lines in the hydraulic
system of the aircraft, it is often relatively difficult and costly
to diagnose and/or repair the hydraulic system. Further, the use of
multiple hydraulic lines must be run to each flap actuator to
ensure redundancy in the system is costly, both in terms of weight
and money. Hence, it is highly desirable to provide a redundant,
flap actuator control system that is simple to install and service
and this is lightweight.
Therefore, it is a primary object and feature of the present
invention to provide a flap actuator that is simple to install and
service.
It is a further object and feature of the present invention to
provide a flap actuator that incorporates redundant load path
design.
It is a still further object and feature of the present invention
to provide a flap actuator that maintains the position of a flap of
an aircraft in response to a compression load thereon by the
flap.
In accordance with the present invention, a flap actuator is
provided for controlling movement of a flap on a wing of an
aircraft. The flap actuator includes a shaft extending along a
longitudinal axis and having a terminal end operatively connectable
to the flap. The shaft is movable between a first retracted
position and a second extended position. A no-back assembly is
operatively connectable to the shaft. The no-back assembly prevents
movement of the shaft toward the retracted position in response to
a compressive force generated by the flap.
The no-back assembly includes a housing for supporting the shaft
and a first gimbal for interconnecting the housing to the wing. A
second gimbal also interconnects the housing to the wing. First and
second pins extend between the housing and the first gimbal, and
interconnect the second gimbal to the first gimbal and the housing.
A mounting pin extends through the first gimbal and is operatively
connectable to the wing.
The flap actuator also includes a ball nut engageable with the
shaft and rotatable about the longitudinal axis. Rotation of the
ball nut in a first direction causes the shaft to move toward the
extended position, while rotation of the ball nut in a second
direction causes the shaft to move toward the retracted position.
The shaft includes a hollow ball screw extending along the
longitudinal axis and an inner bar extending through the ball
screw. A motor having a rotatable drive shaft is also provided. The
drive shaft is rotatable in first and second opposite directions. A
gear assembly translates rotation of the drive shaft to the ball
nut. The gear assembly includes a clutch. The clutch disengages the
drive shaft from the ball nut in response to a predetermined force
thereon.
In accordance with a further aspect of the present invention, a
flap actuator is provided for controlling movement of a flap on a
wing of an aircraft. The flap actuator includes a housing having a
leading end and a trailing end. A ball nut is rotatably supported
in the housing. A ball screw extends along a longitudinal axis and
has a terminal end operatively connectable to the flap. The ball
screw movable between a first retracted position and a second
extended position in response to rotation of the ball nut. A
one-way roller clutch is operatively connectable to the ball nut.
The roller clutch engages the housing and prevents rotation of the
ball nut in a first direction in response to a compressive force on
the ball screw by the flap. A gimbal assembly is connected to the
housing and is connectable to the wing.
The gimbal assembly includes a first gimbal for interconnecting the
housing to the wing and a second gimbal for interconnecting the
housing to the wing. First and second pins extending between the
housing and the first gimbal. In addition, the first and second
pins interconnect the second gimbal to the first gimbal and the
housing. The gimbal assembly also includes a mounting pin extending
through the first gimbal and being operatively connectable to the
wing.
Rotation of the ball nut in a first direction causes the ball screw
to move toward the extended position. Rotation of the ball nut in a
second direction causes the ball screw to move toward the retracted
position. A motor having a rotatable drive shaft is provided. The
drive shaft is rotatable in first and second opposite directions. A
gear assembly translates rotation of the drive shaft to the ball
nut. The gear assembly includes a clutch that disengages the drive
shaft from the ball nut in response to a predetermined force
thereon. An inner bar extends through the ball screw.
In accordance with a still further aspect of the present invention,
a flap actuator is provided for controlling movement of a flap on a
wing of an aircraft. The flap actuator includes a housing having a
leading end and a trailing end. A ball nut is rotatably supported
in the housing. A motor has a rotatable drive shaft that is
rotatable in first and second opposite directions. A gear assembly
translates rotation of the drive shaft to the ball nut. A ball
screw extends along a longitudinal axis and has a terminal end
operatively connectable to the flap. The ball screw is movable
between a first retracted in response to rotation of the ball nut
in a first direction and a second extended position in response to
rotation of the ball nut in a second direction. A one-way roller
clutch is operatively connectable to the ball nut. The roller
clutch engages the housing and prevents rotation of the ball nut in
a first direction in response to a compressive force on the ball
screw by the flap. First and second concentric gimbals are
positioned about the longitudinal axis adjacent the housing. A
first pin extends through the first and second gimbals and being
operatively connected to the housing.
A second pin may also extend through the first and second gimbals
and being operatively connected to the housing and a mounting
arrangement is provided for interconnecting the first gimbal to the
wing. It is contemplated for the first and second gimbals to have a
generally rectangular configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings furnished herewith illustrate a preferred construction
of the present invention in which the above advantages and features
are clearly disclosed as well as others which will be readily
understood from the following description of the illustrated
embodiment.
In the drawings:
FIG. 1 is an isometric view of a flap actuator in accordance with
the present invention mounted on a wing of a conventional
aircraft;
FIG. 2 is an isometric view of the flap actuator of the present
invention;
FIG. 3 is a cross-sectional view of the flap actuator of the
present invention taken along line 3-3 of FIG. 2;
FIG. 4 is a cross-sectional view of a flap actuator of the present
invention taken along line 4-4 of FIG. 3; and
FIG. 5 is a cross-sectional view of a flap actuator of the present
invention taken along line 5-5 of FIG. 2.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to FIGS. 1-2, a flap actuator in accordance with the
present invention is generally designated by the reference numeral
10. As is conventional, an aircraft includes wing 12 projecting
laterally from the fuselage (not shown). Wing 12 includes a forward
end and a trailing end 14. Trailing end 14 of flap 18 includes flap
receiving recess 16 formed therein for receiving flap 18. Flap
receiving recess 16 in trailing end 14 of wing 12 is defined by
first and second generally parallel sides 20 and 22, respectively.
Trailing ends 20a and 22a of corresponding sides 20 and 22,
respectively, intersect trailing edge 14 of wing 12. Leading ends
20b and 22b of corresponding first and second sides 20 and 22,
respectively, intersect frame member 24 of wing 12. Frame member 24
projects laterally from and is operatively connected to the
fuselage of the aircraft.
Flap 18 includes first side 26 pivotably connected to side 20 of
wing 12 and second side 28 pivotably connected to side 22 of wing
12. As is conventional, flap 18 is pivotable about a longitudinal
axis adjacent to and parallel to the leading edge 30 of flap 18 and
movable between an extended and a retraction position. Flap
actuator 10 interconnects flap 18 adjacent the leading edge 30
thereof to frame member 24 of wing 12 in order to control movement
of flap 18.
Flap actuator 10 includes a brushless DC motor 32 rigidly connected
to housing 124 in any suitable manner such as bolts or the like.
Motor 32 is electrically coupled to a controller for receiving
electrical power and converting the same into mechanical power.
Motor 32 includes a drive shaft (not shown) rotatable in first and
second directions in accordance with instructions received from the
controller. It is intended that the mechanical power generated by
motor 32 be transmitted to ball screw 98 through spur gear assembly
36, for reasons hereinafter described. It is noted that in the
drawings, flap actuator 10 is orientated such that motor 32
projects away from the fuselage of the aircraft. It can be
appreciated that flap actuator 10 may be orientated such that motor
32 projects toward the fuselage of the aircraft without deviating
from the scope of the present invention.
Referring to FIG. 4, spur gear assembly 36 includes clutch gear 40
mounted on clutch shaft 44 extending along a longitudinal axis.
Clutch shaft 44 includes a first end 44a rotatably supported by
bearing cage 46 and a second opposite end 44b supporting by bearing
cage 48. Clutch shaft 44 further includes clutch plate 50
projecting radially from a location adjacent first end 44a. A first
set of roller bearings 52 are captured between clutch plate 50 and
a first side of clutch gear 40. A second set of roller bearings 54
are captured between a second side of clutch gear 40 and a first
side of thrust plate 56 which extends about clutch shaft 44.
Belleville spring 58 is captured between a second side of thrust
plate 56 and adjustment nut 60 threaded onto clutch shaft 44.
Pinion 62 projects radially from clutch shaft 44 adjacent second
end 44b thereof.
When assembled, it is intended for belleville spring 58 to compress
thrust plate 56, first and second roller bearings 52 and 54,
respectively, and clutch gear 40 against clutch plate 50 so as to
translate rotation (or more precisely, power) of clutch gear 40 to
clutch shaft 44 under normal operating positions. In operation, the
outer surface of drive shaft of motor 32 meshes with and drives
clutch gear 40 in a user desired direction. If the torque generated
on clutch gear 40 is below a predetermined threshold, rotation of
clutch gear 40 is translated to clutch shaft 44. In the event that
the torque on clutch gear 40 extends a predetermined threshold
(e.g., if a downstream component of flap actuator 10 is locked in
position), clutch gear 40 slips on clutch shaft 44 such that
rotation of clutch gear 40 is not translated to clutch shaft 44.
The torque threshold may be adjusted by varying the spring force
generated by belleville spring 58 on thrust plate 56 via adjustment
nut 60.
Pinion 62 meshes with and drives spur gear 64. Inner diameter of
spur gear 64 is keyed to the outer diameter of bevel shaft 66.
Bevel shaft 66 is rotatably supported by first and second bearing
cages 70 and 72, respectively. Washer 74 and nut 76 combination are
mounted on first end 78 of bevel shaft 66 to maintain first and
second bearing cages 70 and 72, respectively, and spur gear 64
thereon. Second end 80 of bevel shaft 76 includes enlarged bevel
pinion 82 projecting therefrom. Bevel pinion 82 meshes with teeth
84 of bevel gear 86 in order to translate rotation of bevel pinion
82 to bevel gear 86.
Referring to FIG. 3, bevel gear 86 has a splined inner surface 88
that meshes with outer surface 90 of ball nut 92. Threads 94 along
the inner diameter of ball nut 90 mesh with threads 96 along the
outer surface of ball screw 98 for reasons hereinafter described.
Ball screw 98 further includes central passageway 98a adapted for
receiving inner rod 99 therethrough. It is intended for inner rod
99 to maintain the integrity of ball screw 98 in the event of a
fracture of ball screw 98. Inner rod 99, and hence ball screw 98,
extends along a longitudinal axis and includes enlarged head 100 on
a first end 102 thereof. Reinforced aperture 104 extends through
head 200 of ball screw 98. As best seen in FIG. 1, head 100 of ball
screw 98 is interconnected to wing 18 adjacent leading edge 30
thereof through aperture 104. Second end 105 of inner rod 99
includes a seal 107 and nut 109 combination secured thereon for
maintaining ball screw 98 on inner rod 99 and preventing unwanted
material from entering the central passageway 98a.
In order to prevent axial movement (from right to left in FIG. 3)
of ball screw 98 under pressure of a compressive load on the
surfaces of flap 18, and hence movement of flap 18 during operation
of an aircraft, no-back assembly 106 is provided. No-back assembly
106 includes trailing thrust plate 108 and is positioned against
shoulder 110 projecting radially from ball nut 92. Skewed roller
112 is positioned between trailing thrust plate 108 and leading
thrust plate 114. Leading thrust plate 114 is generally tubular and
includes an inner diameter about the outer periphery of ball nut 92
and plate element 116 projecting radially from a first end thereof.
Thrust washer 118 and thrust bearing 120 are positioned between
support surface 122 of housing 124 and plate element 116 of thrust
plate 114. One-way roller clutch 126 is disposed between outer
surface 128 of thrust plate 114 and inner surface 130 of housing
124.
Roller clutch 126 only allows rotation of thrust plate 114 in a
single direction, e.g., clockwise. As such, with ball screw under a
compressive load, thrust plate 108 engages skewed roller 112 and
urges skewed roller against thrust bearing 120. Due to the friction
developed between ball nut flange 110, thrust plate 108, skewed
roller 112 and thrust plate 114, clutch roller 126 prevents further
rotation of ball screw 98 in the clockwise direction.
Housing 124 is interconnected to frame element 124 of wing 12 by
primary and secondary gimbals 134 and 136, respectively, FIG. 5. As
best seen in FIG. 3, it is contemplated for housing 124 to include
main portion 125 and secondary portion 127 attached thereto by a
plurality of through bolts 129, FIG. 2. Housing 124 includes spaced
upper primary gimbal mounting tabs 138 and 140, respectively,
projecting from leading end 125a of main portion 125 of housing
124. Upper primary gimbal mounting tabs 138 and 140, respectively,
are generally U-shaped and include corresponding apertures 142 and
144, respectively, therethrough. Spaced lower primary gimbal
mounting tabs 146 and 148, respectively, project from leading end
125a of main portion 125 of housing 124. Lower primary gimbal
mounting tabs 146 and 184 are generally U-shaped and include
corresponding apertures 150 and 152, respectively therethrough.
Apertures 142 and 144 through upper primary gimbal mounting tabs
138 and 140, respectively, are axially aligned with apertures 150
and 152 though corresponding lower primary gimbal mounting tabs 146
and 148, respectively, for reasons hereinafter described.
Housing 124 further includes spaced upper secondary gimbal mounting
tabs 154 and 156, respectively, extending from leading end 127a of
secondary portion 127 of housing 124. Upper secondary gimbal
mounting tabs 154 and 156 are generally U-shaped and include
corresponding apertures 158 and 160, respectively, therethrough.
Spaced lower secondary gimbal mounting tabs 162 and 164,
respectively, project from leading end 127a of secondary portion
127 of housing 124. Lower secondary gimbal mounting tabs 162 and
164 are generally U-shaped and include corresponding apertures 166
and 168, respectively, therethrough. Apertures 158 and 160 through
upper secondary gimbal mounting tabs 154 and 156, respectively, and
apertures 166 and 168 through lower secondary gimbal mounting tabs
162 and 164, respectively, are axially aligned with each other and
with apertures 142, 144, 150 and 152.
Referring back to FIG. 5, primary gimbal 134 has a generally square
configuration and is defined by upper and lower walls 170 and 172,
respectively having apertures 176 and 178, respectively,
therethrough. Primary gimbal 134 is further defined by first and
second sidewalls 177 and 179, respectively, having corresponding
apertures (not shown) therethrough, for reasons hereinafter
described.
Secondary gimbal 136 also has a square-like configuration and
includes upper and lower walls 180 and 182, respectively. Upper and
lower walls 180 and 182, respectively, of secondary gimbal 136
include corresponding apertures 184 and 186, respectively
therethrough. In addition, secondary gimbal 136 is defined by first
and second sidewalls 188 and 190, respectively, having
corresponding apertures (not shown) therethrough.
In order to mount housing 124 to wing 12, upper gimbal 134 is
positioned such that upper wall 170 of primary gimbal 134 is
received between upper primary gimbal mounting tabs 138 and 140 and
such that lower wall 172 of primary gimbal 134 is received between
lower primary gimbal mounting tabs 146 and 148. In addition,
aperture 176 through upper wall 170 of primary gimbal 134 is
axially aligned with apertures 142 and 144 through upper primary
gimbal mounting tabs 138 and 140, respectively, and such that
aperture 178 through lower wall 172 of primary gimbal 134 is
axially aligned with apertures 150 and 152 through primary gimbal
mounting tabs 146 and 148, respectively.
Secondary gimbal 136 is positioned such that upper wall 180 of
secondary gimbal 136 is received between upper secondary gimbal
mounting tabs 154 and 156 and such that lower wall 182 of secondary
gimbal 136 is received between lower secondary gimbal mounting tabs
146 and 148. Aperture 184 through upper wall 180 of secondary
gimbal 136 is axially aligned with apertures 158 and 160 through
upper secondary gimbal mounting tabs 154 and 156, respectively, and
aperture 186 through lower wall 182 of secondary gimbal 136 is
axially aligned with apertures 166 and 168 through lower secondary
gimbal mounting tabs 162 and 164, respectively.
Once primary and secondary gimbals 134 and 136, respectively, are
positioned as heretofore described, upper pin 190 is inserted
through aperture 142 in upper primary gimbal mounting tab 138;
aperture 176 through upper wall 170 of primary gimbal 134; aperture
144 through upper primary gimbal mounting tab 140; aperture 158
through upper secondary gimbal mounting tab 154; aperture 184
through upper wall 180 of secondary gimbal 136; and aperture 160
through upper secondary gimbal mounting tab 156. In addition, pin
192 is inserted through aperture 150 in lower primary gimbal
mounting tab 146; aperture 178 through lower wall 172 of primary
gimbal 134; aperture 152 through lower primary gimbal mounting tab
148; aperture 166 through lower secondary gimbal mounting tab 162;
aperture 186 through lower wall 182 of secondary gimbal 136; and
through aperture 168 through lower secondary gimbal mounting tab
164. Thereafter, primary gimbal 134 is positioned within mounting
bracket 194 projecting in a trailing direction from frame element
24 of wing 12. Spherical bearings incorporating a mounting pin are
seated in the aperture in sidewall 177 of primary gimbal 134 and in
the aperture in sidewall 188 of secondary gimbal 136 to rigidly
connect flap actuator 10 to mounting bracket 194. Similarily,
spherical bearings incorporating a mounting pin are seated in the
aperture in sidewall 179 of primary gimbal 134 and in the aperture
in sidewall 190 of secondary gimbal 136 to rigidly connect flap
actuator 10 to bracket 194.
In operation, a controller, responsive to pilot control, actuates
motor 32 so as to rotate the drive shaft in a user desired
direction. Spur gear assembly 36 translates rotation of the drive
shaft to bevel gear 86 which, in turn, rotates ball nut 92 about
the longitudinal axis of inner rod 99. Rotation of ball nut 92 is
translated to ball screw 98 which, in turn, moves linearly along
the longitudinal axis of inner rod 99. By way of example, rotation
of ball nut 92 in a clockwise direction causes ball screw 98 to
move in a first linear direction and rotation of ball nut 92 in a
counterclockwise direction causes ball screw 98 to move in a second
opposite linear direction. In such manner, ball screw 98 may be
moved from an extended position to a retracted position, thereby
allowing the position of flap 10 to be adjusted.
During operation of the aircraft, a compressive force (from right
to left in FIG. 3) may be provided on first end 102 of inner rod 99
and on ball screw 98 by flap 18. This compressive force is
translated through no-back assembly 106, as heretofore described,
to housing 124. Thereafter, the compressive load is translated
through pins 190 and 192 to primary and second gimbals 134 and 136,
respectively, and though the spherical bearings of the primary and
second gimbals 134 and 136, respectively, to wing 18. It can be
appreciated that the arrangement of flap actuator 10 provides
redundant load sharing of any compressive force generated by a load
on flap 18. For example, the load may be translated solely by ball
screw 98 if inner rod 99 is disabled and visa-versa. Similarly, the
load may be translated solely by secondary portion 127 of housing
124 if main portion 125 of housing 124 is disabled and visa-versa
or the load may be translated solely by secondary gimbal 136 if
primary gimbal 134 is disabled or visa-versa.
Various modes of carrying out the invention are contemplated as
being within the scope of the following claims particularly
pointing out and distinctly claiming the subject matter that is
regarded as the invention.
* * * * *